19 year old Senna Smith gets more than she bargains for when she buys a autobot car by the name of Bumblebee. But when he transforms in front of her, she's surprisingly open to it. Becoming an asset to the autobots and a loyal friend to them, she's become one of the gang. A human autobot, who'd of thought? But when evils falls to Earth, she realises that blood doesn't make family.